1. Technical Field
The present invention generally relates to the freezing and thawing of biopharmaceuticals and biologics. More particularly, the present invention relates to the preservation and processing by controlled freezing and thawing of small amounts or samples of biopharmaceuticals and biologics, using a reduced-scale system.
2. Background Information
Preservation (storage by freezing) and processing (freezing and thawing) of biopharmaceuticals and biologics (collectively, “bioproducts”), for example, including, but not limited to proteins, cells, antibodies, medicines, plasma, blood, biological buffer solutions, cell culture media, viruses, serum, cell fragments, cellular components, and any other bioproduct, is often required on a large scale using adapted commercial-sized freezing equipment with a subsequent thawing in a room. These methods produce sub-optimal process conditions leading to significant product degradation or loss. For example, bioproducts can be frozen and thawed in containers ranging from 1 to 500 liters.
However, companies and research institutions engaging in the freezing and thawing of bioproducts in such large volumes do so largely without the ability to fully test how the bioproducts will react in the process using the intended equipment. This adds risk and cost, particularly if the bioproducts are damaged in the process.
Even an established routine for preservation and processing of labile bioproducts in small amounts, carried out using small containers such as vials or bottles, and placed in laboratory freezers with a constant temperature setpoint, or in special freezing chambers that can provide changing temperature profiles of the chamber environment, carries risk. Such freezing methods suffer from temperature gradients from container to container, leading to significant differences in the freezing and processing conditions, and subsequent product degradation or/and loss. Further, preservation and processing by placing the small container into a cold nitrogen gas (typically generated from a liquefied nitrogen), cooling them over a certain period of time and then plunging them into the liquid nitrogen may deliver differences in cooling and freezing from container to container as well as uncontrolled freezing across the product volume.
In addition, thawing of small amounts of bioproducts is typically accomplished by leaving them in a room environment, thus leading to slow and uncontrolled thawing which may be detrimental to the product. Rapid and controlled thawing may produce higher quality and minimize or eliminate product degradation and/or loss.
The preservation and processing by freezing and thawing of small amounts of bioproducts is typically associated with supercooling of product prior to freezing. The supercooling of product in small containers depends on the container size, temperature gradients, cooling rate and the presence of ice nucleation sites. The supercooling may differ from container to container, leading to an unrepeatable process. The supercooling is followed by a rapid (flash) freezing of a part of product volume with the temperature rise to about 0° C. and a subsequent slower freezing of the remaining part of the product. Both supercooling and flash freezing can be detrimental to the product, and, since they occur in an unrepeatable way, the product quality may vary among the containers. Minimization or elimination of supercooling can provide uniform product processing and higher overall product quality.
Thus, a need exists for a way to reliably and repeatedly conduct the freezing (without supercooling) and thawing processing for small quantities of bioproducts in a controlled way all across the product volume, thereby providing consistent freezing and thawing conditions.